1. Field of the Invention
This invention relates generally to a dynamically reconfigurable antenna system. More specifically this invention provides a reconfigurable antenna system configured using discrete microwave components which is capable of directing an antenna beam in the direction of greatest signal gain. A smart antenna for portable devices is disclosed which will scan antenna beams to locate the target direction, then re-configure the antenna beam and point the antenna beam to the target direction.
2. Description of Related Art
Conventional antenna systems which may be reconfigured (commonly known as xe2x80x9csmart antennasxe2x80x9d) to adapt the directionality of their beams such that a maximum incoming and/or outgoing signal is achieved have typically involved many high cost and difficult to implement digital circuitry components. Particularly, the phase arrays commonly used to selectively route signals and beamform on one or more antennas have utilized signal converters and digital signal processors (DSP""s) to electronically process each signal, often multiple times during antenna pointing. Additionally, the beam forming networks in conventional antenna systems typically rely on similar digital signal processing elements. Such DSP chips and other electronic components are costly to manufacture and implement in devices compared to discrete microwave components. Additionally, discrete components can also be configured more compactly, enabling smart antenna systems of smaller size that current DSP based systems. Therefore, it would be desirable to create a new low cost and easy to implement smart antenna system which uses for its phase array and beam forming network elements a combination of discrete microwave (analog) components.
The smart antenna system of the current invention may be configured using currently existing and relatively inexpensive microwave components to form phase shifters and switches which form the phase array and beam forming network elements of a smart antenna system. When coupled with a wireless local area network (WLAN) device containing a simple processing unit, signals from the phase array may be processed to determine directionality, and appropriate beam forming signals may be routed through the beam forming network and out an antenna to point the signal. One or more antenna elements are configured such that spatial pointing of beams in opposing directions is possible. A radio frequency (RF) transmission line leads from each antenna element to RF couplers which form a phase shifter for each antenna element. RF switches corresponding to the number of coupler elements in each phase shifter are configured to work with the phase shifters and can be selectively operated to pass signals from each coupler line. To enable beam forming and routing of signals to a WLAN device, a beam forming network (BFN) switch is included which connects with each phase shifter of the phase array.
In one aspect of the current invention, separate phase shifter controller and beam forming network controller elements are included which processing signals from the WLAN device to selectively enable the switching elements of the system.
In another aspect of the current invention, the phase shifter controller and beam forming network controller are included in the WLAN device as functional elements which process signals and selectively enable the switching elements of the system to accomplish beam pointing.
This invention has been described herein in reference to various embodiments and drawings. While this invention is described in terms of the best presently contemplated mode of carrying out the invention, it will be appreciated by those skilled in the art that variations and improvements may be accomplished in view of these teachings without deviating from the scope and spirit of the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense.